ABSTRACT
The inference that the disconnected hemispheres are commonly in a state of simultaneous separate coconscious awareness receives additional support from many bilateral tests that involve concurrent but different sensory input and different motor response from each hemisphere. Experimental investigation of the functional role of the cerebral commissures was stimulated during the early 1940s by a series of clinical reports. Although deep surgical bisections are possible experimentally that includes the roof of the mid-brain, the supramammillary commissure, and even the cerebellum. It was sufficient merely to cut the forebrain commissures that mediate cross communication between the hemispheres proper to prevent interhemispheric transfer of perceptual learning and memory. The collected animal evidence supported the conclusion that each of the disconnected hemispheres develops its own private chain of learning and memory experiences that are cut off from, and inaccessible to, recall through the opposite hemisphere.
